Tuning Frequency for a sub

Discussion in 'Home Theater Projects' started by Dean-P, Feb 23, 2004.

  1. Dean-P

    Dean-P Stunt Coordinator

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    Hi

    I am designing a new sub using Adire Audio's AV8 and playing with WinISD to do so.

    The question I have is how do I know what tuning frequency I want?

    By changing the tuning frequency, I find that I could almost use any size box but of course the tuning is different along with the port size/length.

    I want a small size vented sub to match the Jordan JX92s in a 6L sealed box.

    I planned on making the M8a but my wife wants a "small" speaker and the Jordans got rave reviews...so I guess I will dive into "full range" speakers.

    Thanks Dean
     
  2. GrahamT

    GrahamT Supporting Actor

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    I think I remember that a rule of thumb is to tune near the driver's Fs. That would be around 36 Hz. Also remember to check the the Q of the alignment you are designing. You probably want it somewhere near .7
     
  3. Rob Formica

    Rob Formica Stunt Coordinator

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    Ummmm… actually the idea of tuning a VENTED sub is to extend it's lower frequency response.

    There are several schools of thought on that, but basically the *ideal* theoretical tuning is slightly below the driver/enclosure's natural roll-off (not actually the drivers Fs) so the response curve will give you a perfectly flat plateau. If you increase the enclosure size you can lower the tuning creating a double plateau with slightly reduced output but an extended bass response (often referred to EBS). Doing the opposite (decrease enclosure, raise tuning) has the opposite effect and creates a small bump in the response (often referred to as a punchy sub)

    The Qb is an inherent characteristic of a sealed sub... and 0.7 to 0.5 is considered a flatter audiophile sub while >0.7 is a little more peaky.

    Hope this helps...
    Rob
     
  4. Dean-P

    Dean-P Stunt Coordinator

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    thanks, I guess I will just use the defaults of winISD...
     

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